This invention relates to the purification of riboflavin and, more particularly, it relates to a process wherein riboflavin fermentation solids are upgraded to a product directly usable as an animal feed supplement or adaptable for further purification for pharmaceutical use.
The preparation of riboflavin (vitamin B.sub.2) by fermentation methods is known in the art as is shown, for example, by U.S. Pat. Nos. 2,387,023, 2,445,128, 2,483,855 and 2,571,896. Conventional methods of isolating fermentation produced riboflavin, however, yield a low purity riboflavin which must be upgraded before it is suitable even as an animal feed supplement. The treatment to upgrade the riboflavin is not only time consuming and costly but often involves conditions under which riboflavin is unstable, and gives rise to waste products which are not readily biodegradable.
It is, accordingly, an object of the present invention to provide an improved process for recovering riboflavin. Another object is to provide a process wherein riboflavin fermentation broth or riboflavin fermentation solids are upgraded to an intermediate product either usable as such as an animal feed supplement or suitable for further purification for pharmaceutical use. A further object is to provide an economical process which maximizes riboflavin recovery. These and other objects of the present invention will be apparent from the following description.